2598. Smallest Missing Non-negative Integer After Operations

Description

You are given a 0-indexed integer array nums and an integer value.

In one operation, you can add or subtract value from any element of nums.

• For example, if nums = [1,2,3] and value = 2, you can choose to subtract value from nums[0] to make nums = [-1,2,3].

The MEX (minimum excluded) of an array is the smallest missing non-negative integer in it.

• For example, the MEX of [-1,2,3] is 0 while the MEX of [1,0,3] is 2.

Return the maximum MEX of nums after applying the mentioned operation any number of times.

Example 1:

Input: nums = [1,-10,7,13,6,8], value = 5
Output: 4
Explanation: One can achieve this result by applying the following operations:
- Add value to nums[1] twice to make nums = [1,0,7,13,6,8]
- Subtract value from nums[2] once to make nums = [1,0,2,13,6,8]
- Subtract value from nums[3] twice to make nums = [1,0,2,3,6,8]
The MEX of nums is 4. It can be shown that 4 is the maximum MEX we can achieve.

Example 2:

Input: nums = [1,-10,7,13,6,8], value = 7
Output: 2
Explanation: One can achieve this result by applying the following operation:
- subtract value from nums[2] once to make nums = [1,-10,0,13,6,8]
The MEX of nums is 2. It can be shown that 2 is the maximum MEX we can achieve.

Constraints:

• 1 <= nums.length, value <= 105
• -109 <= nums[i] <= 109

 

Solutions

Solution: Hash Map

• Time complexity: O(n+value)
• Space complexity: O(value)

 

JavaScript

/**
 * @param {number[]} nums
 * @param {number} value
 * @return {number}
 */
const findSmallestInteger = function (nums, value) {
  const counts = Array.from({ length: value }, () => 0);
  let minCount = Number.MAX_SAFE_INTEGER;
  let result = Number.MAX_SAFE_INTEGER;

  for (const num of nums) {
    const mod = ((num % value) + value) % value;

    counts[mod] += 1;
  }

  for (let num = 0; num < value; num++) {
    minCount = Math.min(counts[num], minCount);
    result = Math.min(num + value * minCount, result);
  }

  return result;
};